In many different types of mechanical forming and shaping operations, it is only necessary that the forming tool be subject to a large loading in one direction. For example, a simple expanding die for increasing the diameter of the initial portion of a metal tubing such as an exhaust pipe need only be urged axially into the end of the pipe, all of the load being in this forward direction. While a slight force in a reverse direction may be required to remove the expanding die from the exhaust pipe or other metal tube because of friction and the like, such force is fairly small compared with the main force in forcing the die into the pipe.
Tools of the foregoing type such as an expanding die are normally secured to the machine as by simply threading the tool directly to the end of a hydraulic piston rod or similar machine portion. The work to be shaped or expanded is then clamped and the hydraulic rod will move the die axially into the tube.
Different sized dies are needed for different sized tubes or pipes to be treated and accordingly, a worker must unthread the one die and thread on another die. This attaching and removal of the dies by threading operations is time consuming and oftentimes can result in damage to the threaded portion of the machine itself necessitating complete replacement of a machine part. While mechanisms are known which allow a worker or operator to attach and detach a tool fairly quickly, such mechanisms are for the most part complex in design and costly to fabricate. A need therefore exists for an improved means or mechanism which is simple in design and economical to manufacture and yet enables very rapid attachment and removal of a tool wherein such mechanism is further capable of withstanding large loads in at least one direction and capable of preventing inadvertent separation of the tool when moved in an opposite direction.